EXPERIMENTAL STUDIES ON LONGITUDINAL MODE CHARACTERISTICS OF A HOLLOW-CATHODE HE-CD-LIGHT LASER( WHITE)

A hollow cathode CW He-Cd+ white light laser can oscillate simultaneou sly at three primary colors (five transitions) in a single tube. The f requency characteristics are important parameters in many applications . Therefore, we have investigated the longitudinal mode of our white l ight laser. In our experiment, we have found that the red and green tr ansitions oscillate in a single longitudinal mode in spite of a wide g ain profile and that the blue transition oscillates in a few longitudi nal modes. We consider that this single-mode operation can be caused b y hole burning due to mode competition between the longitudinal modes and the saturation coupling. Furthermore, we measured the pressure bro adenings and the natural linewidths of the five transitions upon chang ing of the He gas pressure in the He-Cd+ white light laser.